Frank Rowand wrote:
Ingo Molnar wrote:
hi Frank - sorry about the late reply, was busy with other things. Your
My turn to be late, but now I'm back from vacation :-).
ppc patches look mostly mergeable, with some small details still open:
* Frank Rowand <[email protected]> wrote:
The patches are:
1/5 ppc_rt.patch - the core realtime functionality for PPC
what is the rationale behind the rt_lock.h changes? The #ifdef
CONFIG_PPC32 changes in generic code are not really acceptable, the -RT
tree tries to keep a single spinlock definition and debugging
primitives, across all architectures.
< stuff deleted >
The second "#ifdef CONFIG_PPC32" is in raw_rwlock_t, making the lock
field signed instead of unsigned. The PPC code uses the value of
-1 to mean write locked, 0 to mean unlocked, and >0 to mean read
locked. With one minor exception, all of the PPC raw_rwlock_t related
code will work properly with an unsigned type because the code that
checks the value of lock is assembly and treats lock as signed. The
one non-assembly code that examines lock as a signed object is in
arch/ppc/lib/locks.c and is disabled unless CONFIG_DEBUG_SPINLOCK is
defined. If CONFIG_DEBUG_SPINLOCK is ever enabled this will be
very evident as each call to __raw_write_unlock() will result in a
printk() warning. The strongest reason I could advance for making
lock signed for PPC32 is that any future C code that checks for a
lock value less than zero will not function correctly and might not
be very obvious.
Thus it is also OK that you left this chunk out of your patch.
< more stuff deleted >
I'm working on the architecture support for realtime on PPC64 now.
If the lock field of struct raw_rwlock_t is a long instead of int
then /proc/meminfo shows MemFree decreasing from 485608 kB to 485352 kB.
Do you have a preference for lock to be long instead of int?
Do you know if any of the other 64 bit architectures would have an
issue with int?
-Frank
--
Frank Rowand <[email protected]>
MontaVista Software, Inc
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